Camera driving module and electronic device

ABSTRACT

A camera driving module includes: a base including a central opening; a casing disposed on the base and including an opening hole corresponding to the central opening; a lens unit movably disposed on the casing; and a focus driving part. The focus driving part includes a carrier, an AF coil element, at least two permanent magnets and a Hall element. The carrier is disposed on the lens unit and movable in a direction parallel to an optical axis. The AF coil element is fixed to the base and faces toward the carrier. The permanent magnets are fixed on one side of the carrier facing toward the base and disposed opposite to each other about the optical axis. The Hall element faces toward a corresponding surface of one of the permanent magnets. The AF coil element and the corresponding surfaces are arranged in the direction parallel to the optical axis.

RELATED APPLICATIONS

This application is a continuation patent application of U.S.application Ser. No. 16/687,430, filed on Nov. 18, 2019, which claimspriority to Taiwan Application 108114321, filed on Apr. 24, 2019, whichis incorporated by reference herein in its entirety.

BACKGROUND Technical Field

The present disclosure relates to a camera driving module and anelectronic device, more particularly to a camera driving moduleapplicable to an electronic device.

Description of Related Art

With the development of semiconductor manufacturing technology, theperformance of image sensors has been improved, and the pixel sizethereof has been scaled down. Therefore, featuring high image qualitybecomes one of the indispensable features of an optical system nowadays.

A conventional lens assembly usually includes a lens barrel and a lenscarrier assembled together by their thread structures. The lens assemblyadjusts the position of the lens barrel with respect to the lens carrierby rotating the lens barrel so as to focus images onto the image surfaceof the image sensor. However, the design requirements of threadstructures may inevitably increase the size of the lens assembly and theassembling complexity. Furthermore, many conventional lens assemblies onthe market usually have a voice coil motor (VCM) as a camera drivermodule for auto focus, and this kind of camera driver module usuallyconsists of several components. For the requirements of accuracy andsmoothness of movement of the lens unit, multiple alignment andcalibration steps are needed during the assembly process of the cameradriver module and the lens unit itself in order to complete the assemblyof those components accurately. As a result, the manufacturingefficiency and yield rate of the camera driver module are thereforeinfluenced.

Accordingly, how to improve the camera driver module for achieving acompact lens assembly and simplifying the assembly process of the lensassembly so as to meet the requirement of high-end-specificationelectronic devices is an important topic in this field nowadays.

SUMMARY

According to one aspect of the present disclosure, a camera drivingmodule includes a base, a casing, a lens unit and a focus driving part.The base includes a central opening. The casing is disposed on the base,and the casing includes an opening hole corresponding to the centralopening of the base. The lens unit is movably disposed on the casing.The focus driving part is configured to drive the lens unit to move in adirection parallel to an optical axis, and the focus driving partincludes a carrier, an AF coil element, at least two permanent magnetsand a Hall element. The carrier is disposed on the lens unit, and thecarrier is movable in the direction parallel to the optical axis. The AFcoil element is fixed to the base, and the AF coil element faces towardthe carrier. The permanent magnets are fixed on one side of the carrierfacing toward the base, and the permanent magnets are disposed oppositeto each other about the optical axis. Each of the permanent magnetsincludes a corresponding surface facing toward the AF coil element. TheHall element faces toward the corresponding surface of one of thepermanent magnets. The Hall element detects a displacement of the lensunit in parallel with the optical axis according to a position of one ofthe permanent magnets. The AF coil element and the corresponding surfaceof the permanent magnets are arranged in the direction parallel to theoptical axis.

According to another aspect of the present disclosure, an electronicdevice includes the aforementioned camera driving module.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be better understood by reading the followingdetailed description of the embodiments, with reference made to theaccompanying drawings as follows:

FIG. 1 is a perspective view of a camera driving module according to the1st embodiment of the present disclosure;

FIG. 2 is an exploded view of the camera driving module in FIG. 1 ;

FIG. 3 is a top view of the camera driving module in FIG. 1 ;

FIG. 4 is a cross-sectional view of the camera driving module in FIG. 3along line A-A′;

FIG. 5 is a schematic view of an AF coil element and a permanent magnetin FIG. 4 repelling each other;

FIG. 6 is a schematic view of the AF coil element and the permanentmagnet in FIG. 4 attracting each other;

FIG. 7 is a perspective view of a camera driving module according to the2nd embodiment of the present disclosure;

FIG. 8 is an exploded view of the camera driving module in FIG. 7 ;

FIG. 9 is a top view of the camera driving module in FIG. 7 ;

FIG. 10 is a cross-sectional view of the camera driving module in FIG. 9along line B-B′;

FIG. 11 is a cross-sectional view of a camera driving module accordingto the 3rd embodiment of the present disclosure;

FIG. 12 is a partial exploded view of the camera driving module in FIG.11 ;

FIG. 13 is one perspective view of an electronic device according to thefourth embodiment of the present disclosure; and

FIG. 14 is another perspective view of the electronic device in FIG. 13.

DETAILED DESCRIPTION

A camera driving module includes a base, a casing, a lens unit and afocus driving part. The base includes a central opening. The casing isdisposed on the base, and the casing includes an opening holecorresponding to the central opening of the base. The lens unit ismovably disposed on the casing. The focus driving part is configured todrive the lens unit to move in a direction parallel to an optical axis.

The focus driving part includes a carrier, an AF (Automatic focusing)coil element, at least two permanent magnets and a Hall element. Thecarrier is disposed on the lens unit and movable in the directionparallel to the optical axis. The AF coil element is fixed to the baseand faces toward the carrier. The permanent magnets are fixed on oneside of the carrier facing toward the base, and the permanent magnetsare disposed opposite to each other about the optical axis. Each of thepermanent magnets includes a corresponding surface facing toward the AFcoil element. The AF coil element and the corresponding surface of thepermanent magnets are arranged in the direction parallel to the opticalaxis. The Hall element faces toward the corresponding surface of one ofthe permanent magnets, and the Hall element detects the displacement ofthe lens unit in parallel with the optical axis according to theposition of one of the permanent magnets. Therefore, the arrangement ofthe permanent magnets, the Hall element and the AF coil element isfavorable for reducing the assembling complexity of the camera drivingmodule, and further reducing repeated and unnecessary steps foralignment and calibration; furthermore, the AF coil element disposed onthe base is favorable for reducing the size of the focus driving part,and achieving feedback control functions in the optical axis direction.

The AF coil element can include a through hole corresponding to thecentral opening of the base. Therefore, it is favorable for bettercontrolling the assembling precision of the AF coil element and thebase, and achieving an even and consistent efficiency of electromagneticeffect between the AF coil element and the permanent magnets.

The base can further include a side wall structure surrounding thecentral opening of the base. The side wall structure can include alateral surface facing toward the permanent magnets, and the lateralsurface can have an even number of first grooves. Therefore, the firstgrooves may be configured with additional rigid mechanism (e.g., thespherical bearing elements described below) disposed therein so as tominimize the assembly failure rate of the camera driving module.

The first grooves can extend in the direction parallel to the opticalaxis. Therefore, it is favorable for reducing the difficulty of theinjection molding for manufacturing the base so as to increase theconsistency of the dimensions of the base, and thus a tilt of the cameradriving module caused by the base is prevented.

The permanent magnets can be fixed on a carrying surface of the carrier,and the carrying surface can have an even number of second groovesrespectively corresponding to the first grooves. Therefore, the evennumber of second grooves is favorable for the linear movement stabilityof the lens unit in a two-dimensional plane.

According to the present disclosure, the camera driving module canfurther include a plurality of spherical bearing elements disposedbetween one of the first grooves and corresponding one of the secondgrooves. Therefore, a larger rigidity of the spherical bearing elementis favorable for increasing the consistency of quality of the cameradriving module when the spherical bearing elements are configured withmechanisms having a preload force (e.g., the configuration of themagnetic plate and permanent magnets); furthermore, the sphericalbearing element is favorable for reducing assembling complexity.

Both the number of the first grooves and the number of the secondgrooves can be four. Therefore, a configuration of the camera drivingmodule including four first grooves and four second grooves is favorablefor preventing unpredictable tilt of the lens unit when the lens unitmoves, thereby increasing the linear movement stability of the lens unitin the optical axis direction.

According to the present disclosure, the camera driving module canfurther include a magnetic plate. The side wall structure can include atleast three side walls extending from the central opening of the basetowards the opening hole of the casing in the direction parallel to theoptical axis. The magnetic plate and one or more first grooves aredisposed on one of the side walls, and the magnetic plate correspond toone of the permanent magnets. Therefore, it is favorable for applying apreload force on the camera driving module by the magnetic platecorresponding to the permanent magnets, such that the spherical bearingelements disposed between the first and second grooves satisfy therequirement of stabilizing the module, thereby significantly increasingthe accuracy and straightness of movement of the lens unit in theoptical axis direction.

The base can be a unitary element. Therefore, it is favorable forreducing the amount of required components and additional assemblyprocess, and also minimizing the cumulative errors during collaboration.Moreover, the side wall structure can be in a shape of closed ring.Therefore, when the base is a unitary element and the side wallstructure is a close-ring shaped structure, it is favorable for reducingthe use of frame elements, the corresponding assembling process andrepeated alignment and calibration steps during assembling, therebysignificantly increasing the efficiency of assembly of the cameradriving module.

The base can further include at least three gate portions surroundingthe central opening of the base. Therefore, with respect to an injectionmolded plastic part with an opening hole, the design of plural gateportions surrounding the central opening is favorable for reducing thefailure rates of dimension variation and appearance defects, and alsofavorable for obtaining a better control of the shrinkage of the plasticpart.

The lens unit and the carrier can be integrally formed as a coaxialunitary element, and the coaxial unitary element defines an inner spacefor accommodating at least one optical lens element. Therefore, it isfavorable for omitting a dispensing process for attaching the lens unitto the carrier, and thereby satisfying the conditions of harsherenvironmental tests; furthermore, the requirement of assembling accuracyof the lens unit and the carrier can be significantly improved byensuring the precision of the injection mold, and the product dimensionconsistency can be ensured in mass production.

According to the present disclosure, the camera driving module canfurther include a stopper mechanism configured to restrict the movementrange of the carrier in the direction parallel to the optical axis. Thestopper mechanism can include an upper stopper element, and the upperstopper element can be closer to the opening hole of the casing than thecarrier to the opening hole. Therefore, the upper stopper element withspecific thickness can be configured as a space separator/adjuster forpreventing noise made by the collision of the lens unit with the carrierduring focusing.

The stopper mechanism can further include at least two lower stopperportions respectively disposed on opposite sides of the central openingof the base, and the lower stopper portions and the base can beintegrally formed as a unitary element. The lower stopper portions canextend from the base towards the opening hole of the casing. Therefore,when the lower stopper portions and the base are formed as a unitaryelement, the lower stopper portions can be fine adjusted by mold designso as to prevent the interference between the carrier and the centralopening area of the base, thereby reducing impact noise.

The number of the lower stopper portions can be three or more, and thegate portions of the base can be respectively and correspondinglydisposed on the lower stopper portions; that is, the gate portions aredisposed on respective lower stopper portions. Therefore, the gateportions are favorable for reducing the complexity of the groove shapeof each gate portion so as to effectively increase the productionefficiency of injection molded parts and reduce the defect rate;furthermore, the gate portions disposed on respective lower stopperportions is favorable for making good use of the thickness of the lowerstopper portions to adjust the mold design of the gate portions, makingthe design of the gate portions is not limited to the form ofconventional base featuring a plate shape with an opening hole.

When a distance parallel to the optical axis between the AF coil elementand the permanent magnets is Dc, and a distance parallel to the opticalaxis between the Hall element and the permanent magnets is Dh, thefollowing condition can be satisfied: 0.0<Dc/Dh≤1.0. Therefore, it isfavorable for fully utilizing the space of the camera driving module soas to reduce the amount of unused space among components. Furthermore,when an area on the AF coil element surrounded by the voice coil islarger than the surface of the Hall element facing toward the permanentmagnet, Dc/Dh can be equal to 1.0 (i.e., the AF coil element and theHall element are located on the same plane), such that the Hall elementcan accurately detect the displacement of the permanent magnet inparallel with the optical axis. Please refer to FIG. 4 , which shows aschematic view of Dc and Dh according to the 1st embodiment of thepresent disclosure.

According to the present disclosure, the aforementioned features andconditions can be utilized in numerous combinations so as to achievecorresponding effects.

According to the above description of the present disclosure, thefollowing specific embodiments are provided for further explanation.

1st Embodiment

FIG. 1 is a perspective view of a camera driving module according to the1st embodiment of the present disclosure. FIG. 2 is an exploded view ofthe camera driving module in FIG. 1 . FIG. 3 is a top view of the cameradriving module in FIG. 1 . FIG. 4 is a cross-sectional view of thecamera driving module in FIG. 3 along line A-A′. In this embodiment, acamera driving module 1 includes a base 11, a casing 12, a lens unit 13,a focus driving part 14, a plurality of spherical bearing elements 16, amagnetic plate 17 and a stopper mechanism 18.

The base 11 is a unitary element which includes a central opening 110,four gate portions 111 and a side wall structure 112. These gateportions 111 and the side wall structure 112 are all disposed around thecentral opening 110.

The casing 12 is disposed on the base 11, and the casing 12 includes anopening hole 120 corresponding to the central opening 110 of the base11.

The lens unit 13 is disposed on the casing 12, and the lens unit 13 canbe driven by the focus driving part 14 to be movable in a directionparallel to an optical axis O. In detail, the focus driving part 14includes a carrier 141, an AF coil element 142, two permanent magnets143 and a Hall element 144.

The carrier 141 is disposed on the lens unit 13, and the carrier 141 ismovable in the direction parallel to the optical axis O. The carrier 141has a carrying surface 1410 facing toward the base 11.

The AF coil element 142 is fixed to the base 11 and faces toward thecarrier 141. The AF coil element 142 includes a through hole 1420corresponding to the central opening 110 of the base 11. In thisembodiment, the AF coil element 142 is, but not limited to, a flexibleprinted circuit coil (FPC coil), which allows at least two auto focuscoils to be integrated as a unitary one-piece element.

The permanent magnets 143 are fixed on the carrying surface 1410 of thecarrier 141, and the permanent magnets 143 are disposed opposite to eachother about the optical axis O. Each of the permanent magnets 143includes a corresponding surface 1430 facing toward the AF coil element142. Moreover, the AF coil element 142 and the corresponding surface1430 of the permanent magnets 143 are arranged in the direction parallelto the optical axis O.

The Hall element 144 faces toward the corresponding surface 1430 of oneof the permanent magnets 143, and the Hall element 144 detects thedisplacement of the lens unit 13 in parallel with the optical axis Oaccording to the position of one of the permanent magnets 143.

The side wall structure 112 of the base 11 is in a shape of closed ring,and the side wall structure 112 includes a lateral surface 1120 and fourside walls 1121. The lateral surface 1120 faces toward the permanentmagnets 143, and the side walls 1121 extend from the central opening 110of the base 11 towards the opening hole 120 of the casing 12 in thedirection parallel to the optical axis O. The lateral surface 1120 hastwo first grooves 1122, and the carrying surface 1410 of the carrier 141has two second grooves 1411 respectively corresponding to the firstgrooves 1122. In this embodiment, the first grooves 1122 and the secondgrooves 1411 all extend in the direction parallel to the optical axis O.

The spherical bearing elements 16 are disposed between each pair offirst groove 1122 and second groove 1411. The magnetic plate 17 and thefirst grooves 1122 are all disposed on one of the side walls 1121 andlocated on opposite sides of the side wall 1121. The magnetic plate 17corresponds to one of the permanent magnets 143.

The stopper mechanism 18 includes an upper stopper element 181 and fourlower stopper portions 182. The upper stopper element 181 is disposednear the opening hole 120 of the casing 12. The upper stopper element181 is closer to the opening hole 120 of the casing 12 than the carrier141 to opening hole 120, and the upper stopper element 181 is disposedbetween the carrier 141 and the opening hole 120 of the casing 12. Thelower stopper portions 182 are respectively disposed on opposite sidesof the central opening 110 of the base 11. The lower stopper portions182 and the base 11 are integrally formed as a unitary element, and thelower stopper portions 182 extend from the base 11 towards the openinghole 120 of the casing 12. Furthermore, the gate portions 111 of thebase 11 are respectively and correspondingly disposed on the lowerstopper portions 182.

When a distance parallel to the optical axis O between the AF coilelement 142 and the permanent magnets 143 is Dc, and a distance parallelto the optical axis O between the Hall element 144 and the permanentmagnets 143 is Dh, the following condition is satisfied: Dc/Dh=0.6.

According to the present disclosure, the lens unit 13 of the cameradriving module 1 is driven to move in the direction parallel to theoptical axis O by the magnetic effect of electric current. Specifically,please refer to FIG. 5 and FIG. 6 . FIG. 5 is a schematic view of an AFcoil element and a permanent magnet in FIG. 4 repelling each other. FIG.6 is a schematic view of the AF coil element and the permanent magnet inFIG. 4 attracting each other. In this embodiment, one end of thepermanent magnet 143 closer to the AF coil element 142 is the north poleN. As shown in FIG. 5 , when an electric current in the AF coil element142 flows in a direction Dout pointing out of the plane of the page onthe left-hand side of FIG. 5 , and flows in a direction Din pointinginto the plane of the page on the right-hand side of FIG. 5 , the AFcoil element 142 generates a magnetic field repelling the permanentmagnets 143, making the permanent magnets 143 bring the carrier 141 andthe lens unit 13, which are assembled together, to move in a directionas indicated by an arrow D1. On the other hand, as shown in FIG. 6 ,when the electric current in the AF coil element 142 flows in thedirection Din pointing into the plane of the page on the left-hand sideof FIG. 6 , and flows in the direction Dout point out of the plane ofthe page on the right-hand side of FIG. 6 , the AF coil element 142generates a magnetic field attracting the permanent magnets 143, makingthe permanent magnets 143 bring the carrier 141 and the lens unit 13 tomove in a direction as indicated by an arrow D2. Therefore, the focusdriving part 14 is utilized for image focusing.

2nd Embodiment

FIG. 7 is a perspective view of a camera driving module according to the2nd embodiment of the present disclosure. FIG. 8 is an exploded view ofthe camera driving module in FIG. 7 . FIG. 9 is a top view of the cameradriving module in FIG. 7 . FIG. 10 is a cross-sectional view of thecamera driving module in FIG. 9 along line B-B′. In this embodiment, acamera driving module 2 includes a base 21, a casing 22, a lens unit 23,a focus driving part 24, a plurality of spherical bearing elements 26and a stopper mechanism 28.

The base 21 is a unitary element which includes a central opening 210,four gate portions 211 and a side wall structure 212. These gateportions 211 and the side wall structure 212 are all disposed around thecentral opening 210.

The casing 22 is disposed on the base 21, and the casing 22 includes anopening hole 220 corresponding to the central opening 210 of the base21.

The lens unit 23 is disposed on the casing 22, and the lens unit 23 canbe driven by the focus driving part 24 to be movable in a directionparallel to an optical axis O. In detail, the focus driving part 24includes a carrier 241, an AF coil element 242, two permanent magnets243 and a Hall element 244.

The carrier 241 is disposed on the lens unit 23, and the carrier 241 ismovable in the direction parallel to the optical axis O. The carrier 241has a carrying surface 2410 facing toward the base 21.

The AF coil element 242 is fixed to the base 21 and faces toward thecarrier 241. The AF coil element 242 includes a through hole 2420corresponding to the central opening 210 of the base 21.

The permanent magnets 243 are fixed on the carrying surface 2410 of thecarrier 241, and the permanent magnets 243 are disposed opposite to eachother about the optical axis O. Each of the permanent magnets 243includes a corresponding surface 2430 facing toward the AF coil element242. Moreover, the AF coil element 242 and the corresponding surface2430 of the permanent magnets 243 are arranged in the direction parallelto the optical axis O.

The Hall element 244 faces toward the corresponding surface 2430 of oneof the permanent magnets 243, and the Hall element 244 detects thedisplacement of the lens unit 23 in parallel with the optical axis Oaccording to the position of one of the permanent magnets 243.

The side wall structure 212 of the base 21 is in a shape of closed ring,and the side wall structure 212 includes a lateral surface 2120 and fourside walls 2121. The lateral surface 2120 faces toward the permanentmagnets 243, and the side walls 2121 extend from the central opening 210of the base 21 towards the opening hole 220 of the casing 22 in thedirection parallel to the optical axis O. The lateral surface 2120 hasfour first grooves 2122, and the first grooves 2122 are respectivelylocated on two of the side walls 2121 corresponding to the permanentmagnets 243. In addition, the carrying surface 2410 of the carrier 241has four second grooves 2411 respectively corresponding to the firstgrooves 2122. In this embodiment, the first grooves 2122 and the secondgrooves 2411 all extend in the direction parallel to the optical axis O.

The spherical bearing elements 26 are disposed between each pair offirst groove 2122 and second groove 2411.

The stopper mechanism 28 includes an upper stopper element 281 and fourlower stopper portions 282. The upper stopper element 281 is disposednear the opening hole 220 of the casing 22. The upper topper element 281is closer to the opening hole 220 of the casing 22 than the carrier 241to the opening hole 220, and the upper stopper element 281 is disposedbetween the carrier 241 and the opening hole 220 of the casing 22. Thelower stopper portions 282 are respectively disposed on opposite sidesof the central opening 210 of the base 21. The lower stopper portions282 and the base 21 are integrally formed as a unitary element, and thelower stopper portions 282 extend from the base 21 towards the openinghole 220 of the casing 22. Furthermore, the gate portions 211 of thebase 21 are respectively and correspondingly disposed on the lowerstopper portions 282.

When a distance parallel to the optical axis O between the AF coilelement 242 and the permanent magnets 243 is Dc, and a distance parallelto the optical axis O between the Hall element 244 and the permanentmagnets 243 is Dh, the following condition is satisfied: Dc/Dh=0.6.

3rd Embodiment

FIG. 11 is a cross-sectional view of a camera driving module accordingto the 3rd embodiment of the present disclosure. FIG. 12 is a partialexploded view of the camera driving module in FIG. 11 . In thisembodiment, a camera driving module 3 includes a base 31, a casing 32, alens unit 33 and a focus driving part 34. The casing 32 is disposed onthe base 31, and the lens unit 33 is movably disposed on the casing 32.

The focus driving part 34 includes a carrier 341, an AF coil element342, two permanent magnets 343 and a Hall element 344.

The lens unit 33 and the carrier 341 are integrally formed as a coaxialunitary element M, and the coaxial unitary element M defines an innerspace INS for accommodating a plurality of optical lens elements L.

The AF coil element 342 is fixed to the base 31 and faces toward thecarrier 341.

The permanent magnets 343 are fixed to the carrier 341 and disposedopposite to each other about an optical axis O. Each of the permanentmagnets 343 includes a corresponding surface 3430 facing toward the AFcoil element 342. Moreover, the AF coil element 342 and thecorresponding surface 3430 of the permanent magnets 343 are arranged inthe direction parallel to the optical axis O.

The Hall element 344 faces toward the corresponding surface 3430 of oneof the permanent magnets 343, and the Hall element 344 detects thedisplacement of the lens unit 33 in parallel with the optical axis Oaccording to the position of one of the permanent magnets 343.

4th Embodiment

FIG. 13 is one perspective view of an electronic device according to thefourth embodiment of the present disclosure. FIG. 14 is anotherperspective view of the electronic device in FIG. 13 .

In this embodiment, an electronic device 4 is a smartphone including thecamera driving module 1 disclosed in the 1st embodiment, a flash module41, a focus assist module 42, an image signal processor 43, a userinterface 44 and an image software processor.

When a user captures images of an object, the light rays converge in thecamera driving module 1 to generate an image(s), and the flash module 41is activated for light supplement. The focus assist module 42 detectsthe object distance of the imaged object to achieve fast auto focusing.The image signal processor 43 is configured to optimize the capturedimage to improve image quality. The light beam emitted from the focusassist module 42 can be either conventional infrared or laser. The userinterface 44 can be a touch screen or a physical button. The user isable to interact with the user interface 44 and the image softwareprocessor having multiple functions to capture images and complete imageprocessing. The image processed by the image software processor can bedisplayed on the user interface 44.

The smartphone in this embodiment is only exemplary for showing thecamera driving module 1 of the present disclosure installed in anelectronic device, and the present disclosure is not limited thereto.The camera driving module 1 can be optionally applied to optical systemswith a movable focus. Furthermore, the camera driving module 1 featuresgood capability in aberration corrections and high image quality, andcan be applied to 3D (three-dimensional) image capturing applications,in products such as digital cameras, mobile devices, digital tablets,smart televisions, network surveillance devices, dashboard cameras,vehicle backup cameras, multi-camera devices, image recognition systems,motion sensing input devices, wearable devices and other electronicimaging devices.

The foregoing description, for the purpose of explanation, has beendescribed with reference to specific embodiments. It is to be noted thatthe present disclosure shows different data of the differentembodiments; however, the data of the different embodiments are obtainedfrom experiments. The embodiments were chosen and described in order tobest explain the principles of the disclosure and its practicalapplications, to thereby enable others skilled in the art to bestutilize the disclosure and various embodiments with variousmodifications as are suited to the particular use contemplated. Theembodiments depicted above and the appended drawings are exemplary andare not intended to be exhaustive or to limit the scope of the presentdisclosure to the precise forms disclosed. Many modifications andvariations are possible in view of the above teachings.

What is claimed is:
 1. A camera driving module, comprising; a basecomprising a central opening; a casing disposed on the base, and thecasing comprising an opening hole corresponding to the central openingof the base; a lens unit movably disposed on the casing; and a focusdriving part configured to drive the lens unit to move in a directionparallel to an optical axis of the lens unit, and the focus driving partcomprising: a carrier disposed on the lens unit, and the carrier beingmovable in the direction parallel to the optical axis; an AF coilelement fixed to the base, and the AF coil element facing toward thecarrier; at least two permanent magnets fixed on one side of the carrierfacing toward the base, wherein the at least two permanent magnets aredisposed opposite to each other about the optical axis, and one of theat least two permanent magnets comprises a corresponding surface facingtoward the AF coil element; and a Hall element facing toward one of theat least two permanent magnets; wherein the Hall element detects adisplacement of the lens unit in parallel with the optical axisaccording to a position of one of the at least two permanent magnets,and the AF coil element and the corresponding surface are arranged inthe direction parallel to the optical axis; wherein a distance parallelto the optical axis between the AF coil element and the at least twopermanent magnets is Dc, a distance parallel to the optical axis betweenthe Hall element and the at least two permanent magnets is Dh, and thefollowing condition is satisfied:0.0<Dc/Dh≤1.0.
 2. The camera driving module of claim 1, wherein the AFcoil element comprises a through hole corresponding to the centralopening of the base.
 3. The camera driving module of claim 1, whereinthe base further comprises a side wall structure surrounding the centralopening, a lateral surface of the side wall structure faces toward theat least two permanent magnets, and the lateral surface has an evennumber of first grooves.
 4. The camera driving module of claim 3,wherein each of the first grooves extends in the direction parallel tothe optical axis.
 5. The camera driving module of claim 4, wherein thelens unit and the carrier are integrally formed as a coaxial unitaryelement, and the coaxial unitary element defines an inner space foraccommodating at least one optical lens element.
 6. The camera drivingmodule of claim 3, wherein the at least two permanent magnets are fixedon a carrying surface of the carrier, and the carrying surface has aneven number of second grooves respectively corresponding to the firstgrooves.
 7. The camera driving module of claim 6, further comprising aplurality of spherical bearing elements, wherein the plurality ofspherical bearing elements are disposed between one of the first groovesand corresponding one of the second grooves.
 8. The camera drivingmodule of claim 6, wherein the number of the first grooves is four, andthe number of the second grooves is four.
 9. The camera driving moduleof claim 3, further comprising a magnetic plate, wherein the side wallstructure comprises at least three side walls, each of the at leastthree side walls extends from the central opening of the base towardsthe opening hole of the casing in the direction parallel to the opticalaxis, the first grooves and the magnetic plate are disposed on one ofthe at least three side walls, and the magnetic plate corresponds to oneof the at least two permanent magnets.
 10. The camera driving module ofclaim 3, wherein the base is a unitary element, and the side wallstructure is in a shape of closed ring.
 11. The camera driving module ofclaim 10, wherein the base further comprises at least three gateportions surrounding the central opening of the base.
 12. The cameradriving module of claim 1, further comprising a stopper mechanismconfigured to restrict a movement range of the carrier in the directionparallel to the optical axis, wherein the stopper mechanism comprises anupper stopper element, and the upper stopper element is closer to theopening hole of the casing than the carrier to the opening hole.
 13. Thecamera driving module of claim 12, wherein the stopper mechanism furthercomprises at least two lower stopper portions respectively disposed onopposite sides of the central opening of the base, the at least twolower stopper portions and the base are integrally formed as a unitaryelement, and each of the at least two lower stopper portions extendsfrom the base towards the opening hole of the casing.
 14. The cameradriving module of claim 13, wherein the base further comprises at leastthree gate portions, the number of the at least two lower stopperportions is three or more, and the at least three gate portions arerespectively and correspondingly disposed on the at least three lowerstopper portions.
 15. An electronic device, comprising the cameradriving module of claim 1.